This invention relates generally to the monitoring of pipelines and, more particularly, to the monitoring of sound in an in-ground pipeline.
In-ground pipelines have found various uses. For example and without unnecessary limitation, in-ground pipelines are used extensively in the transmission of various materials between selected points or locations. Natural gas is one example of a material frequently transmitted via in-ground pipelines.
As will be appreciated, there is a common need or desired to be able to effectively monitor such below ground surface transmissions such as to avoid or otherwise preclude the occurrence of an accident or other improper conveyance of the material being transmitted through the pipeline. For example, there is a need and a demand for a monitoring method that permits the detection of the status of such a pipeline, such as the flow state of valves or other flow control elements included in the pipeline system, without undesirably interrupting or otherwise disrupting operation.
Further it is known that damage to in-ground pipelines can occur directly as a result of acts of nature such as earthquakes and landslides, for example. The damage resulting to in-ground pipelines as a result of the occurrence of such acts typically occurs on a sufficiently large scale such that multiple pipe joints are affected and detection of the occurrence of such damage is relatively easy. Pipeline damage can, however, occur due to the act of a third party, i.e., a party other than the owner or operator of the pipeline. Such damage is known as xe2x80x9cthird-party damage.xe2x80x9d When the damage due to an act of a third party causes an immediate rupture of a pipe, little can be done via on-line monitoring to prevent an ensuing incident. However, many third-party contacts with pipelines can cause damage that does not result in an immediate pipeline failure but rather can cause damage that may, with time, lead to a pipe failure such as in the form of a leak or a catastrophic rupture. For example, time and pressure cycling to which a pipeline might normally be subjected may, with time, eventually lead to the occurrence of such a pipeline failure, with such a pipeline failure sometimes referred to as a xe2x80x9cdelayed failure.xe2x80x9d In view of the above, the occurrence of such third-party contact and the effective detection thereof has proven to be a persistent problem.
While sounds associated with contact with a pipeline can be transmitted through the pipeline and detected at substantial distances from the point of contact via highly sensitive acoustic sensors, the high sensitivity of such sensors can produce or result in a significant number of false calls arising from sources other than by contact with the pipeline. For example, sources such as passing vehicles and weather conditions such as thunder and rain can produce or result in false calls to a normal sound detection and monitoring method and system.
In view of the consequences of the failure of an in-ground pipeline due to third-party contact, particularly when coupled with the extensive construction related with urban expansion and encroachment of the right-of-way commonly associated with many of such in-ground pipelines, there is a need and a demand for a method and system for monitoring in-ground pipelines and, in particular, detecting contact with a pipeline and proactively warn of the potential for the occurrence of damage associated therewith. In particular, there is a need and a demand for a reliable acoustic monitoring method and system that can effectively eliminate false calls such as may arise from at least certain noncontact events.
A general object of the invention is to provide an improved method and system for the monitoring of sound in an in-ground pipeline and the use thereof, such as for the detection of contact with such an in-ground pipeline.
A more specific objective of the invention is to overcome one or more of the problems described above.
The general object of the invention can be attained, at least in part, through a method for monitoring sound in an in-ground pipeline involving the processing of at least one first signal received from at least one first in-ground acoustic sensor and at least one second signal received from at least one associated second in-ground acoustic sensor, wherein the first in-ground acoustic sensor is in contact with the in-ground pipeline and the at least one associated second in-ground acoustic sensor is spaced from both the first in-ground acoustic sensor and the in-ground pipeline.
The prior art has generally failed to provide a method and system for the monitoring of sound in an in-ground pipeline in a manner that is as effective as may be desired. In particular, the prior art has generally failed to provide a method and system for the monitoring of an in-ground pipeline in a sufficiently unintrusive and effective manner such as to permit the detection of contact with the pipeline and proactively warn of the potential for the occurrence of damage associated with such contact while also minimizing or avoiding the occurrence of false signals such as may result from at least certain noncontact events with the pipeline of interest.
The invention further comprehends a method for detecting contact with a pipeline in the ground. In accordance with one embodiment of the invention, such method includes:
detecting an acoustic parameter associated with the pipeline and transmitting a corresponding first input signal to a processor;
detecting an acoustic parameter associated with the ground adjacent the pipeline and transmitting a corresponding second input signal to the processor; and
comparing the first and second input signals in the processor in accordance with at least one signal comparison technique to produce a product signal as a function of the difference between the first and second input signal.
In accordance with another embodiment of the invention, a method for detecting contact with an in-ground pipeline includes:
receiving in a processor a first input signal from at least one first in-ground accelerometer and at least one second input signal from at least one associated second in-ground accelerometer, wherein the first in-ground accelerometer is in contact with an in-ground pipeline and the at least one associated second in-ground accelerometer is spaced from both the first in-ground sensor and the in-ground pipeline; and
processing the first input signal and the at least one second input signal in the processor on at least one basis selected from the group consisting of time analysis, frequency analysis and a combination thereof to produce an output signal as a function of the difference between the first input signal and the second input signal.
Other objects and advantages will be apparent to those skilled in the art from the following detailed description taken in conjunction with the appended claims and drawings.